1. Field of the Invention
The present invention relates to sensing and monitoring systems for use for use in association with subsea structures. More particularly, the present invention the relates to sensing systems that can be applied onto the actuator of the subsea structure. Additionally, the present invention relates to system whereby the position of an actuator can be monitored and data relating to the position of the actuator stored.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
As the need for hydrocarbon increases throughout the world, there is a constant demand for the increasing of offshore oil production. Typically, offshore oil production will include a variety of subsea structures that are utilized so as to control the flow of hydrocarbons from the well. Typically, blowout preventers are placed upon the wellhead. The blowout preventers will include a wide variety of mechanisms that are used so as to control the flow of fluids from the wellhead. These blowout preventers often include rams and valves which operate for the purpose of closing the wellhead in emergency or “blowout” conditions.
There are a variety of other subsea structures that are employed for the production of hydrocarbons. In addition to the blowout preventer stack, the other equipment can include subsea manifolds, Christmas trees, umbilical termination assemblies, subsea distribution units, manifolds, PLETS, PLEMS and capping stacks. Each of these subsea control systems has a variety of operational parameters that can be monitored by gauges, sensors, and other equipment.
Under certain circumstances, disasters can occur subsea. As in the case of the Macondo oil spill in the Gulf of Mexico, the blowout preventer became defective and, as a result, lacked the ability to control the flow of hydrocarbons. This resulted in a blowout. Although the blowout preventer was monitored at the surface, there was no definitive evidence, at the subsea location, of the events that transpired which led to the blowout. Under certain circumstances, the monitoring of the blowout preventer at the surface of the body of water is not always recorded. Additionally, it is possible for the operators to manipulate the recorded data at the surface of the body of water. As such, a need has developed so as to be able to record the data associated with a particular piece of subsea equipment which is tamper-proof, accurate, and verifiable.
In the event of a subsea explosion, most of the gauges, sensors, displays and monitors associated with the subsea piece of equipment become destroyed. This is especially the case in the subsea environment where many of the various small components that are left as a result of an explosion are virtually untraceable. As such, it becomes impossible to retrieve data from a very large event, such as an explosion, has occurred subsea.
One of the problems associated with the use of subsea monitoring equipment is the need for battery power. Batteries can eventually discharge and data can be lost, as a result. It becomes very difficult to maintain such batteries in their fully charged capacity. Since the subsea equipment can be used over the course of many years, the potential for battery discharge is great. As such, most companies have avoided the use of such subsea monitoring equipment.
The various subsea structures employed a wide variety of valves, actuators and control systems. Typically, the operation of such valves and actuators has been monitored by an inferred relationship to pressure. For example, an operator will know that a valve has been actuated when an increase or decrease in the monitored pressure occurs. However, this is a very indirect assessment of the proper operation of the control system of the subsea structure Changes in pressures can occur even when a particular valve is working improperly or incompletely. Often, the actuator associated with the valve does not move in its entire intended range. The partial opening or closing of a valve can lead to major problems in the production of hydrocarbons or can eventually lead to emergency or blowout conditions. As such, a need exists to be able to properly monitor the specific movement of the actuator and/or valve in a direct realtime manner.
Under other circumstances, the operation of actuators and/or valves is visually observed from the remotely-operated vehicle (ROV). The camera equipment associated with the ROV is positioned so as to observe a telltale associated with the actuator. As such, a visual observation of actuator movement can occur. This is quite difficult to manage since an ROV will need to be positioned for such observation. Additionally, the murky conditions of the subsea environment will create difficulties in the ability to properly observe the true movement of the telltale. The visual observation of the operation of the actuator is not very precise. As such, the visual observation may lead one to believe that the actuator is properly working even when the valve is not completely opening or closing.
After an emergency or blowout situation, it is desirable to be able to record the proper functioning of the various actuators. As such, the monitoring of the exact position of the actuator can produce data that is particularly relevant in ascertaining fault or responsibility associated with such emergency or blowout conditions. This is particularly important since the inferred observation of the operation of such valves and/or actuators could lead to one that conclusion that all the valves are operating properly.
It is important in the operation of the subsea structures that repairs and maintenance be carried out whenever it should occur as quickly as reasonably possible so as to avoid the possibility of emergency conditions affecting the entire subsea system.
In the past, various patents have issued relating to communicating with and monitoring of subsea systems. For example, U.S. Pat. No. 4,122,498, issued on Oct. 24, 1978 to R. E. Dyer, describes a data recording apparatus including a data recording circuit for recording event data provided by a data source on a first track of a magnetic tape and a time recording circuit which effects the recording of time reference data for the event data on a second track of the tape. The time recording circuit includes a digital clock which provides encoded data representing month, day, hours and minutes for recording on the tape. There is also an identification data source which provides encoded data representing an identification number for the data source for recording on the tape. The time and identification data are recorded on the tape in a bi-phase format.
U.S. Pat. No. 7,261,162, issued on Aug. 28, 2007 to Deans et al., shows a subsea communications module which includes an interface to communicate with a surface facility over a communications link using a packet-based protocol. The communications link can be implemented with a fiberoptic line, a wire-based line, and/or other types of communications lines.
U.S. Pat. No. 7,711,322, issued on May 4, 2010 to Rhodes et al., provides an underwater communications system and method. The underwater communications system is provided so as transmit electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically-insulated, magnetically-coupled antenna transmits the compressed, modulated signals. The receiver that has an electrically-insulated, magnetic-coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor decompresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form.
U.S. Pat. No. 7,953,425, issued on May 31, 2011 to L. B. Jordan, teaches a universal event/data recorder system. This recorder system provides a common bridge between various event/data recorders found on mobile assets. The universal event/data recorder system includes an onboard segment that is capable of interfacing with any manufacturer's event/data recorder device. Additionally, the universal event/data recorder system also includes a remote segment for accessing, analyzing and reviewing data collected from any of a plurality of event/data recorders. The universal event/data recorder system may allow accessing data from various event/data recorders using any of a number of communication means including the Internet and a wireless communication network.
U.S. Patent Publication No. 2005/0283276, published on Dec. 22, 2005 to Prescott et al., describes a real-time subsea monitoring and control system for pipelines. This method includes installing a monitoring system for measuring at least one parameter of interest. The monitoring system includes various monitoring sensors placed at selected locations along the pipeline. A series of measurements are taken using the monitoring sensors in real-time. The measurements are analyzed to identify anomalous conditions existing in the pipeline being monitored. An autoadaptive corrective action is implemented based upon the real-time measurement of the parameter of interest.
U.S. Patent Publication No. 2008/0217022 shows a subsea communication multiplexer. This is a system for communicating between a surface facility and a subsea production control system. The water surface communications device has at least one communication interface. A communications device is functionally associated with a wellhead or subsea structure proximate the water bottom. The water bottom communications device has at least one communication interface. A communication channel extends between the surface communication device and the water bottom communication device. A multiplexer is functionally coupled to the communication interface on each of the surface and water bottom communication devices. At least two remote devices are functionally coupled to the water bottom multiplexer. The remote devices include at least one of a sensor and a control. At least two corresponding devices are coupled to the surface multiplexer. The corresponding devices include at least one of a signal acquisition device and a control signal generating device.
U.S. Patent Publication No. 2008/0289876, published on Nov. 27, 2008 to King et al., teaches a method and system for monitoring auxiliary operations on mobile drilling units. This system includes at least one sensor configured to measure a parameter related to a start time and a stop time of at least one auxiliary operation on the drilling unit. The system includes a data acquisition device configured to determine a start time and a stop time of the auxiliary operation from measurements made by the sensor. The data acquisition device includes a data recorder for recording elapsed time between the start time and the stop time.
U.S. Patent Publication Nos. 2010/0135122, 2010/0159827 and 2011/0177779, published to Rhodes et al., describe underwater communication systems that are provided to transmit electromagnetic and/or magnetic signals to a remote receiver. The transmitter includes a data input. A digital data compressor compresses data to be transmitted. A modulator modulates compressed data onto a carrier signal. An electrically-insulated, magnetically-coupled antenna transmits the compressed modulated signals. The receiver has an electrically-insulated, magnetically-coupled antenna for receiving a compressed, modulated signal. A demodulator is provided for demodulating the signal to reveal compressed data. A de-compressor decompresses the data. An appropriate human interface is provided to present transmitted data into text/audio/visible form.
Various patents and publications have also issued relating to position sensors. For example, U.S. Pat. No. 5,331,152, issued on Jul. 19, 1994 to S. P. Fenton, shows a sensor for a valve member or choke for oil and gas production. This sensor detects the position of an object that moves along a linear path. The sensor includes a holder with input and output fiberoptic tubes extending into the holder. The ends of the fiberoptic tubes are located adjacent to the moving object. The moving object has a reflecting portion which will reflect light back when located in registry with the fiberoptic tubes.
U.S. Pat. No. 7,231,837, issued on Jun. 19, 2007 to R. W. McCoy, Jr., describes an angular movement detector and networks of angular movement detectors for controlling movement of an articulated arm. The angular movement detectors are disposed within or proximate to joints in one or more members of articulated arms and linked via one or more communications networks to a controller so as to provide angular movement data to the controller for use in controlling movement of the articulated arm. At least one sensor is disposed in the angular movement detector and adapted to detect an orientation of a magnetic field and produce a digital signal representation of the sensed magnetic field. A magnetic field generator is disposed external to the angular movement detector.
U.S. Pat. No. 7,296,486, issued on Nov. 20, 2007 to Holtz et al., provides an angular movement detector that is disposed within or proximate to joints in one or more members of articulated arms. These detectors are linked by way of one or more communications networks to a controller to provide angular movement data to the controller for use in controlling movement of the articulated arm. The angular movement detector comprises a hydraulic motor drive sensor adapter which uses an eccentrically rotating main shaft to rotate a drive shaft to which the main shaft is loosely connected to further rotate a socket housing about a constant central axis. The sensor is able to detect an orientation of an electromagnetic field and can comprise one or more anisotropic magneto-resistive sensors, Hall-effect sensors, or the like. A trigger is provided that can include a magnet, or other source of a magnetic field, where the generated magnetic field is strong enough to be detected by the sensor.
U.S. Patent Publication No. 2003/0052670, published on Mar. 20, 2003 to A. Miszewski, provides non-invasive detector for a well. This detector detects magnetic field disturbances resulting from the movement of equipment through a pipe of magnetic material. A pair of linear ferrite magnetic elements are positioned in end-to-end relationship and aligned with the axis of the pipe. A Hall effect drive is positioned between the magnetic elements. The ferrite rods concentrate magnetic field changes due to the equipment through the Hall effect device. Two pairs of elements are spaced around the pipe and a second set of pairs of elements are spaced along the pipe. The detector is attached to an existing pipe or mounted in an instrument package which passes through the pipe.
U.S. Patent Publication No. 2007/0289373, published on Dec. 20, 2007 to J. Sugiura, describes a rotary steerable steering tool having a sensor arrangement for measuring downhole dynamic conditions. The rotary steerable tools include a rotation rate measurement device disposed to measure a difference in rotation rate between a drive shaft and an outer, substantially non-rotating housing. A controller is configured to determine a stick/slip parameter from the rotation rate measurements.
It is an object of the present invention to provide a sensing and monitoring system that is able to directly measure the movement of a valve and/or actuator within the subsea system.
It is another object of the present invention to provide a sensing and monitoring system which allows the position of an actuator and/or valve to be monitored in realtime.
It is still another object of the present invention to provide a sensing and monitoring system in which the data associated with the particular actuator and/or valve can be stored in a “black box”-type structure.
It is another object of the present invention to provide a sensing and monitoring system that can be effectively utilized in the deep subsea environment.
It is another object of the present invention to provide a sensing and monitoring system in which the system can be retrofitted to existing actuators.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.